Preparation of nicotinonitrile



Patented Dec. 13, 1949 Moses L. Crossley, Piaipfield, Victor L. King and mo H N theY; 'B undlBmoki nd There.

dore F. Schulz, Westfield N,; J. assigirors American Cyanamid Coinpanyi N. Y., a corporation Maine awi a pp ication August.9,- 1944,

ial 8. 90,: l

hi lllfillfiipn relates j'to the, preparation of; lder'iyativeslTMqifiIl articularly, thejn ielates tb "an improved process of coil. 7

bfoxiiopyridineft'of3-cyanopyliidine,

fi it si r' 1e 'f'orriinjercial iiii'po'rtance because th body can synthesize rrbmtuesematenms one of the components of Vitamin B. Consequently the ts eeea qmhs r u npr imc a angi nigotinarnide have become of increasing sjp e thfi formul oi nicotinic acid is coorr an apparently desirable starting material for its pneparation is pyridine which is commercially available in large quantities. However, no satis-, I factory;process adapted for use on a 'commer-t cia' lly jacceptable,scale has been available. It is therefore the principal object of the presentf inyentioni to provide a process wherebynicotinic acidbr nicotinamide, can be producedirom pyridine m large qi iantities without encountering problems which cannot be handled in plant-scale equ prrient.

According to the process of the present inven i tiop, A pyridine is converted to 3-bromopyridin.

This imay'bellc'arriedbut by any desired process it m ay be done by direct prmnina; tiojijori'ef sligh l focess being shown, forexarnplq bi; 133

isimeri:

azjiitfie fatter can be converted to sic-angers fie af bya relatively simple hydrolysis.

More specifically, 3-bromopyridine,is place l En gjl'ert andfMcElvain', 51' J. A. C. S page 8632,..-

g1$the;;prcflductron, of niootinic j acid or 5 v altantQfiicQtbPifii-idlhms become of,.con;"' the period over. whichthe 'cbpper salt is beingt then treated t3; break ug 2,, time to complete the reaction unde ,xefluxpondh tions. Preferably, b prrt negessarily,"the eiuip ment in which the reactiorii's'carried out should be provided with. cooling means to slow dotvn the reaction .ifi-the lattfhecoir'is' too violent durin' added;

The. reaction between. S-bromopyridine .vand

the. metal cyanideproduces 4a metal salt .v 015.;

.v E4 e qeess-pit e r enti ene. tion lthejreaction jlrl'riie iiateiya'fter r flux has stqppe'dds jslgowlyzupdl red in to a large, 5: 1 ai t. br' h i lr s fiat 'dii P ringisldone l's 'owl y udit thelaslt part ,of lthej residue begoigqes p e6 before it. is poured, 'it' I n b .s f enedPrsnqe a mins-L hi r ts. i in the' production' of La largelnurrib er oflsmall s l'P le-t fl ivi fi a$ lY. liId.-Wh e Thejgljound slurry ogf thje' 'coppenco rnplex is" "the copper compound? Thiscan befibne iri'an'y D e'sired mariner. A pref a is. ofthe requisite a be avoided fliecaiiseigairyjlextiyfeis si v.reageiit re e with riitiiIe-i.

mm: i's'olaitionv otthe .nicotinonitrlle is carried outbi Iofl :theho'pper sludge, ifiaking the Y L ,filtratel alkaline a'nd'ifadding suflicient sodium chlorideato precipitate the nicotinonitrile... The. lattenislthen.extractedawitha suitable solvent such .as benzene" dried (and finaILysubjectedtQ.

fractional distil latienjoremoye thesolventngnd F i yield a pure product. Carriedv out according {tar 3 the process of the present invention, yields as high as 70-75% of the theoretical, based on the original 3-bromopyridine used, are readily obtained, whereas by previously known methods the yields seldom exceeded 40-45% and then were obtained only with extreme difl'iculty.

It will be seen, therefore, that the process of the present invention involves six features.

1. Control of the exothermic reaction between cuprous cyanide and bromopyridine by regulated addition of the cyanide;

2. Pouring the reaction product into an excess of rapidly agitated water to produce pellets of the copper complex;

3. Reduction of the copper complex by grind ing to a workable slurry;

4. Decomposition of the copper complex with sodium sulfhydrate or an equivalent operation;

5. The solvent extraction of the desired product; and

6. Purification by vacuum distillation.

The invention will be more fully illustrated in conjunction with the following example which is to be taken as illustrative only and not by way of limitation. All parts are by weight unless otherwise noted.

Example 1 25 mole parts of 3-bromopyridine were charged into a reaction vessel fitted with a condenser and stirring equipment. Heat was provided by means of a fluid bath maintained at 180185 C. Heating was continued until the bromopyridine began to reflux gently. At this point, 27.5 mole parts of cuprous cyanide were slowly added at a rate ju'st sufficient to maintain the reaction at a rapid boil. Heating and agitating were continued for about ten minutes after all the copper salt had been added, after which it was poured into a large excess of water which was rapidly agitated. In this way only about 1% of the melt remained in the reaction vessel.

Water was decanted from the resultant pellets and the latter wet-ground to a thick, almost dry, paste. This paste was reslurried in a part of the drowning water and the slurry rapidly agitated. At this point the slurry had a pH of 5 to 6.5. A solution of sodium sulfhydrate liquor (33.6% by volume) was slowly added, keeping the temperature at about 24-26 C. by cooling as necessary until the pH of the resultant solution was between 3.5 and 6. About 19 mol parts were required. It should be noted that if all the copper were present in the cuprous state, theoretical requirements would be 13.75 mol parts.

Subsequently, the copper sulfide sludge was filtered off and washed, the washings being added to the mother liquor and the filtrate made alkalinewith sodium hydroxide to pH of 9-10 and 40.mol parts of sodium chloride added. This procipitated an oil which rapidly solidified and was taken up in successive small portions of benzene. The benzene extract was dried over anhydrous. sodium sulfate. agent, the benzene filtrate'was fractionally distilled, two outs being taken, the first up-to 98 C. at 33 millimeters and the second up to 104-406 C. at 32 millimeters. Fraction 1 was an oil at room temperature but solidified on cooling in ice water, remelting however, when being returned to room temperature. Fraction 2 was a solid at room temperature. The total yield was 67% of the theory, based on the 3-bromopyridine origi-" nallyused'. 1

Example 2 100 parts of 3-bromopyridine were heated until they refluxed gently. 63 parts of cuprous-cyanide were added slowly enough to prevent excess boiling, but to maintain a continuous reflux. The resultant brown syrupy liquid was heated until reaction was complete and then drowned in a solution comprising sodium cyanide 39 parts, water 159 parts, and ice 159 parts. The precipitated pellets which formed were ground to a homogeneous paste and then treated with an additional 39 parts of sodium cyanide and sufficient drowning liquor to just dissolve. When the solution was complete, sufiicient sodium chloride was added to form a saturated solution. The aqueous supernatant solution of free nicotinonitrile was then worked up as in Example 1.

Example 3 Cyanation of 100 parts of 3-bromopyridine was carried out as in Example 2, the syrupy liquid -'-being drowned in 320 parts of rapidly agitated I ,water.

Example 4 Example 3 was repeated up to the point at which the copper complex was slurried. A copper complex in this instance was broken down by the addition of a slight excess of sodium hydroxide while stirring the mixture. The precipitate of inorganic copper compounds was filtered off, the nicotinonitrile salted out, extracted out, and the extract distilled as in the preceding examples.

Example 5 Again the procedure of Example 2 was repeated heated until reaction was complete.

up to the point of preparing the slurry of the copper complex. The slurry was treated with a slight excess over the theoretical amount of sodium sulfide in aqueous solution and then Again the aqueous nicotinonitrile solution was clarified by filtration, salted out, extracted with benzene and the benzene extract treated by fractional distillation. Again the product was obtained in good yield.

The technique of converting nicotinonitrile to nicotinic acid or the latter to nicotinamide is relatively simple and does not form a part of the present invention. By way of illustration the 0 nicotinonitrile may be converted to nicotinic acid After filtering off the drying by refluxing in a solution of alcoholic sodium hydroxide, distilling off the alcohol, taking it up at acid in water, and purifying it by careful reprecipitation.

We claim: 1. In a process for the preparation of a copper bromide-nicotinonitrile complex in particulate form, the steps which consist in heating 3-bromopyridine to about the boiling point thereof; adding cuprous cyanide thereto at a controlled rate just suflicient to maintain the reaction mixture at moderate ebullition until reaction substantially ceases, whereby a hot crude pourable copper bromideenicotinonitrile complex is formed, and

I5 pouring the syrupy reacted mixture into a large volume of substantially neutral water, whereby pellets of said crude complex are formed.

2. A process according to claim 1, wherein the reaction of said 3-bromopyridine with said cuprous cyanide is performed under reflux.

3. A process according to claim 1, wherein said water is agitated.

MOSES L. CROSSLEY. VICTOR L. KING. ELMORE H, NORTHEY. THEODORE F. SCHOLZ.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Country Date Great Britain 1936 OTHER REFERENCES Number 

